Valve Lash Adjustment

[pontiacgp]

Steve I agree with your method and I am sure it works perfect. But on any motor you have only one opportunity to do that on dry lifters. Once it starts you now have oil filled lifters forever. Maybe he should have said this only works on fresh lifters? I absolutely hate adjusting poly-locks on a running motor. But what else can you do? If you adjust for zero lash on a filled lifter, then add whatever extra turn for pre-load, when the motor starts the lifter will open the valves too much until a couple of cycles pass when it can bleed down and self adjust. That gets you the crappy running he spoke of. So I guess that this is a great way to adjust a dry motor but he should have mentioned that it HAS to be a dry motor.

If you are concerned about the .030 to .035 you can depress the lifter spring on an engine that was recently run. Without any oil pressure the lifter spring can be depressed. My engine was left all winter but the lifters still had oil in them but I was able to depress the lifter spring more than .035

 

[bracketchev1221]

Not sure what he is talking about. Lifters do not get hard after the engine is off. Hydraulic lifters only get hard with oil pressure, otherwise they bleed off and become soft until oil pressure pumps them up. When I worked in the machine shop building engines, at the state he is, I would spin the engine around until each pair of lifters is on the base circle. Easy to see with the intake off. Then move the pushrod up and down, until the slack was out. Then 1/2 turn. That was it. And we ALWAYS would squirt oil into the lifters before installation. For roller lifters, we put them in a container of oil before installation to bleed the air out. On assembled engines, I use the EO/IC procedure because I deal with many engines, multiple firing orders, and large duration cams. The last one I did was 282/290 @.050 with a 4/7 swap firing order. For a hydraulic cam engine, I still use the 1/2 turn method and then mark the nut with a white dot. That way, later I can see if the nuts moved, or if I need to go a little more, I have a reference point and can just tighten all of them without having to rotate the engine.

 

[Bonnewagon]

Steve, you can only do that on a lifter where the oil hole is open to the oil gallery as it can bleed down. Once the oil hole is above the oil gallery it goes solid hard. That is how a hydraulic lifter works. So I guess that if you rotated the engine as he did and only tried adjusting the loose rockers on the base circle then it would work? I'm very interested in this as I have a friend that needs help. He did the idiotic dance where you go from "#1 cyl int" then to "#6 cyl exh" jumping back and forth all over the place. As a result a couple of valves hung open and it backfired out the tunnel ram intake like bombs going off. I stepped in and did my adjustments by removing the spark plugs and killing the ignition. I had him cranking the engine and as I watched every valve open and close I adjusted for zero lash plus 1/4 turn. I just went from front to back along each head. He could not believe how great the engine ran! I only did 1/4 turn to prove my point that he screwed up the adjustments and to let it run a while before final adjustment. But then I wanted to do it over adding 3/4 turn as that is what GM recommends, and being an impatient SOB he never let me finish. If I can do it this new way then it will save a lot of time and probably get better results. EDIT: I think Braketchev1221 answered my question and makes sense.

 

[pontiacgp]

since you brought up the point about oil in the lifter I looked up a few articles and they all said that when the engine is turned off and there is no oil pressure the valve seat can be depressed....in this diagram there is a recess where the body oil hole is so when there is no oil pressure it can bleed down to that hole but if that lifter stopped spinning with the hole at the higher side it may not bleed much if at all. With my roller lifters they do not spin but I never looked to see where the body oil hole is located.

 

[bracketchev1221]

There will always be clearance from the lifter body to the bore, so regardless of where it is over time it will bleed down especially under spring pressure. It is the rapid motion of the lifter in the bore and being pressure fed that prevents it from bleeding down when running.

 

[Bonnewagon]

So then this method will work regardless of whether the lifter is dry or oil filled? Makes sense even though it contradicts what he said in the video. I'll have to try that on the engine I mentioned before.

 

[pontiacgp]

So then this method will work regardless of whether the lifter is dry or oil filled? Makes sense even though it contradicts what he said in the video. I'll have to try that on the engine I mentioned before.

The only question that remains is are you ok to do this so soon after your operation?

 

[Bonnewagon]

I saw my GP yesterday. NO heavy lifting. I can ride my bike next week.

 

[pontiacgp]

That is good news....I'll be seeing my GP this weekend and no appointment necessary.....😎

 

[Bonnewagon]

I can just imagine what it will be like trying to turn a push rod that is only exposed by a couple of inches. That and the fact it will be oily and slimy. Then I also realized that this will be only used on poly-locks. A stock jam nut only has one adjustment- 20lbs torqued. The best tool for this will be the wrench that has the open end that fits the nut and the T-allen that fits the nut lock. He refused to buy that too but I could use one in my collection. I will definitely make him buy the beers.